1. Field of the Invention
This invention is in the field of electrochemical cells, such as those used to convert chemical energy into electrical energy (e.g. fuel cells), having means to provide relative motion between an electrode and an electrolyte—including means for rotating an electrode (U.S. Class 429/67-69, Int. Class H01M), to achieve accelerated chemical reaction rates promoted by Taylor Vortex Flows (TVF) and Circular Couette Flows (CCF).
2. Description of Related Art
Electrochemical cells, such as fuel cells used to convert chemical energy into electrical energy, are well known. In general, fuel cells comprise an anode electrode reactive with a hydrogen-based or reducing fuel (reductant) and a cathode electrode reactive with an oxidizer. The electrodes are separated from each other by an electrolyte fluid that transports, 1) protons from the anode to the cathode where they react with both the oxidizer and with electrons travelling from the anode through an external electrical circuit to the cathode to form a compound, such as water or 2) hydroxyl ions from the cathode to the anode to form water there.
Fuel cells rely on molecular kinetics, e.g., temperature, reactant concentration and catalysis to induce molecules to react at a catalytic surface. Prior art teaches that there are five principal methods to increase reaction rates and thereby increase output current. They are 1) raise temperature and/or pressure, 2) improve catalyst activity, 3) augment electrode surface activity by adding other forms of resonant energy to electrodes or to reactants (U.S. Pat. No. 7,482,072 to, Brooks et al), 4) increase reactant transport rates to or from reaction surfaces (mass transport) and 5) raise the catalyst surface area/electrode area ratio.
Operational data for prior art fuel cell electric currents disclose that these currents do not exceed 1.0 ampere/cm2 and generally are in a range of 0.4 to 0.8 ampere under load at about 0.75 volt. This equates to about 0.3 to 0.5 watt/cm2 of anode or cathode surface. Some of the more common limits are imposed by a) mass-transport losses of ions moving through electrolytes, b) surface losses at catalysts caused by intermediate reaction products attracted to active sites, c) mass-transport losses of fuel, oxidizer and ions moving within electrodes to reach catalysts where they can react and d) overpotential decrement due to limited catalyst activity.
In most fuel cells, a proton exchange membrane (also known as a polymer electrolyte membrane or PEM) that is permeable to protons, but not to some fuels or oxidizers, is located within the electrolyte to prevent wasteful and dangerous cross-over of fuel and oxidizer within the electrolyte. The membrane causes both decreased conversion efficiency and increased loss of fuel or oxidizer.